|The weight coffin is an insert for our 3700 series coffin. It is designed to secure weights from 1/8th of an OZ. All the way to your big 2 OZ punching weights. no more broken boxes, chipped weights/paint, or time wasted searching for the right weight. Holds every size tungsten weight, fits in every bass mafia 3700 coffin, protects finish and paint on weights, same durable design as our coffins.